Electric pump and modularized fuel supply system with such electric pump

ABSTRACT

An electric pump ( 1 ) comprises a pump section ( 3 ) drawing a fluid into the pump compartment ( 11 ), a motor section ( 2 ) including a rotatable armature ( 14 ) in the motor compartment ( 10 ) driving the pump section ( 3 ). The pump ( 1 ) also comprises an outlet port ( 45 ) allowing a drawn and pressurized fluid to be discharged to the outside of the pump ( 1 ), and a communicating opening ( 48 ) discharging a portion of the fuel from the pump section ( 3 ) into the motor compartment ( 10 ). The fluid from the pump compartment ( 11 ) is discharged directly from the outlet port ( 45 ), not through the motor compartment ( 10 ). The portion of the fluid from the pump section ( 3 ) flows into the motor compartment ( 10 ) via the communicating opening ( 48 ), and is finally discharged from the second outlet port ( 30 ) after passing through the motor compartment ( 10 ).

This application claims priority to Japanese patent application serial number 2004-220108, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electric pump used, for example, as an in-tank fuel pump for a pumping fuel stored in a automobile fuel tank, and a modularized fuel supply system with such an electric pump.

2. Description of the Related Art

Referring now to FIG. 30, the prior art fuel pump utilizing an electric pump will be described. This type of fuel pump is known as a turbine-type or impeller-type pump. The fuel pump 201 integrally includes a motor section 202 and a pump section 203 provided at one end of the motor section (at the lower end in FIG. 30). The outer shell of the fuel pump 201 is a pump casing 205, which includes a generally tubular shell 206, a motor cover 207 sealing one end of the tubular shell (the upper end in FIG. 30), a pump cover 208 sealing the other end of the tubular shell (the lower end in FIG. 30), and a pump housing 209 overlayingly provided on the pump cover 208 to partition the inside area of the tubular shell 206 into a motor compartment 210 and a pump compartment 211.

The motor section 202 consists, for example, of a brush-type DC motor, including magnets 213 secured within the tubular shell 206, and an armature 214 rotating within the tubular shell 206. The armature 214 includes an armature body 215 having an iron core, a coil, a commutator 216 and the like, and a shaft 218 provided through the axis of the armature body 215. One end (the upper end in FIG. 30) of the shaft 218 is rotatably supported within the motor cover 207 by a bearing 221. On the other hand, the other end (the lower end in FIG. 30) of the shaft 218 passes through the pump housing 209, rotatably supported therewithin by a bearing 222. The lower end of the shaft 218, which projects into the pump compartment 211, is a connecting portion 219 having a certain modified cross section such as a D-shaped cross section.

The motor cover 207 incorporates a brush 224 slidingly contacting with the commutator 216 of the armature 214, a spring 225 pushing the brush 224 onto the commutator 216, and the like. Furthermore, the motor cover 207 includes a connector section 228 having a terminal 227 electrically connected with the brush 224. Thus, the armature 214 is rotated by energizing the coil (not shown) of the armature 214 via the terminal 227, the brush 224 and the commutator 216. In addition, the motor cover 207 is provided with an outlet port 230 upwardly opening to the outside of the fuel pump 201. The outlet port 230 also communicates with the motor compartment 210.

Referring to the pump section 203, the pump compartment 211 rotatably receives a generally disk-shaped impeller 234. The outer periphery of the impeller 234 is provided with a plurality of vane grooves 235 in a circumferential predetermined interval. The vane grooves 235 on the top surface of the impeller 234 are in mirror symmetry with the vane grooves 235 of the bottom surface of the impeller 234. The vane grooves 235 on the both surfaces communicate with each other through communicating holes 236. The center of the impeller 234 is, on the other hand, provided with a shaft hole 238. The shaft hole 238 has a certain modified cross section such as a D-shaped cross section cooperating with the connecting portion 219 of the shaft 218 of the armature 214. The connecting portion 219 of the armature 214 is engagingly inserted into the shaft hole 238 so as to transmit the torque to the impeller 234.

As indicated as reference numerals 209 a and 208 a, the wall surfaces of the pump housing 209 and the pump cover 208, which respectively face the top and the bottom surfaces of the impeller 234, are provided with generally cylindrical recesses 239 corresponding respectively to the top and the bottom surfaces around the shaft hole 238 of the impeller 234. The recess 239 facing the top surface of the impeller 234 is substantially symmetrical to the recess 239 facing the bottom surface of the impeller 234. The recesses 239 of the pump cover 208 and the recess 239 of the pump housing 209 respectively define bearing compartments 263. Also, the wall surfaces 209 a and 208 a of the pump housing 209 and the pump cover 208 are provided with generally arc-shaped flow channel 240 corresponding respectively to the vane grooves 235 on the top and the bottom surfaces of the impeller 234.

The pump cover 208 is provided with an inlet port 242 downwardly opening to the outside of the fuel pump 201. The inlet port 242 also communicates with the starting end of the flow channel 240. Furthermore, the pump cover 208 is provided with a vapor vent 276 downwardly opening to the outside of the fuel pump 201. The vapor vent 276 also communicates with a predetermined point between the starting end and the terminating end of the flow channel 240. On the other hand, the pump housing 209 is provided with an outlet port 245 opening to the motor compartment 210. The outlet port 245 also communicates with the terminating end of the flow channel 240. It is to be noted that the first outlet port 245 and the vapor vent 276 in FIG. 30 are in fact disposed apart at a predetermined angle along the circumferential direction of the impeller 234.

Now described is the operation of the above-mentioned fuel pump 201. Referring to the motor section 202, the armature 214 is firstly rotated by energizing the coil (not shown) of the armature 214. Then, cooperating with the shaft 218 of the armature 214, the impeller 234 is rotated in a predetermined direction that creates a pumping action. This causes the flow channel 240 to draw a fluid or a fuel from the inlet port 242 of the pump cover 208. The fuel is applied with kinetic energy from the vane grooves 235 both on the top and the bottom surfaces of the impeller 234, which communicate with each other through the communicating holes 236. The fuel is transferred through the flow channels 240 in both the pump cover 208 and the pump housing 209, directing from the starting ends to the terminating ends. In the course of the transfer, the fuel is gradually pressurized. The fuel transferred to the terminating ends of both the flow channels 240 is then discharged from the outlet port 245 of the pump housing 209 into the motor compartment 210 of the motor section 202. Furthermore, after passing through the motor compartment 210, the fuel is discharged from the outlet port 230 of the motor cover 207. It is to be noted that the description “first outlet port” refers to the fuel outlet port 245 of the pump section 203, while the description “second outlet port” refers to the fuel outlet port 230 of the motor section 202. On the other hand, the vapors contained in the fuel transferred in the pumping cycle involving the rotation of the impeller 234 is vented from the vapor vent 276 of the pump cover 208 to the outside of the fuel pump 201.

Next, the prior art fuel supply system, including the above-mentioned fuel pump (electric pump) 201 as an in-tank fuel pump, is described referring to FIG. 31 in which the flow path diagram of the fuel supply system is shown. Other than the fuel pump 201, the fuel supply system 284 includes a high-pressure filter 330, a pressure regulator 286 and low-pressure filter 332 in a modular configuration. The modularized fuel pump 201 is disposed in a reservoir cup (or merely referred to as a cup) mounted within a fuel tank 292. It is to be noted that the high-pressure filter 330 is referred to as a “fuel filter” or “back-end filter.” Also, the pressure regulator 286 is referred to as “regulator valve,” while the low-pressure filter 332 is referred to as a “suction filter” or “front-end filter.”

The fuel pump 201 draws and pressurizes the fuel within the reservoir cup 290 to discharge the fuel into the high-pressure filter 330. The high-pressure filter 330 removes foreign particles in the pressurized fuel discharged from the fuel pump 201, and then discharges the pressurized fuel into the pressure regulator 286. It is to be noted that the high-pressure filter 330 includes a fine filter element (not shown) for removing foreign particles in the fuel in order to avoid having the particles reach the pressure regulator 286 or an injector 312. On the other hand, the pressure regulator 286 controls the fuel pressure of the pressurized fuel discharged from the high-pressure filter 330, draining the excess, pressurized fuel into the reservoir cup 290. The pressurized fuel controlled with regard to fuel pressure by the pressure regulator 286 is discharged into a fuel supply line 311 outside of the fuel tank 292. As shown in FIG. 31, the fuel supply line 311 is connected with the injector 312. Meanwhile, the low-pressure filter 332 removes foreign particles drawn from within the reservoir cup 290 into the fuel pump 201. The low-pressure filter 332 includes a coarse filter element (not shown) for removing foreign particles in order to avoid having the particles reach the fuel pump.

With reference to the fuel supply system 284 described above, when the fuel pump 201 is activated, the fuel within the reservoir cup 290 is drawn via the low-pressure filter 332, pressurized, and fed into the high-pressure filter 330. Then, the fuel, having passed through the high-pressure filter 330, passes through the pressure regulator 286 and flows into the fuel supply line 311 outside of the fuel tank 292. The fuel flowing into the fuel supply line 311 is fed into the injector 312. On the other hand, the pressure regulator 286 controls the fuel pressure and drains any excessive highly pressurized fuel into the reservoir cup 290.

It is to be noted that of the foreign particles contained in the fuel, relatively large particles (referred to as □ in FIG. 31) are removed through the low-pressure filter 332. Meanwhile, relatively small particles (referred to as Δ in FIG. 31) and brush-wear particles or motor-generated particles (referred to as ◯ in FIG. 31) are removed through the high-pressure filter 330.

The above-mentioned fuel supply system 284 (shown in FIG. 31) is disclosed, for example, in U.S. Pat. No. 6,739,354 by Oku et al. which is assigned to the same assignee as the present invention. The disclosure of U.S. Pat. No. 6,739,354 is incorporated herein by reference in its entirety. The above-mentioned fuel pump 201 (shown in FIG. 30) is disclosed, for example, in Japanese Laid-Open Publication No. 2002-303219. Also, the fuel pump including the first outlet port 245, from which the fuel within the pump section 203 is directly discharged to the outside of the pump, is disclosed, for example, in Netherlands Patent No. 6806734.

The above-mentioned fuel pump 201 (shown in FIG. 30) discharges the pressurized fuel from the second outlet port 230 after permitting the fuel into the motor compartment 210 from the first outlet port 245. At the same time, the motor section 202 of the fuel pump 201, the commutator 216 of the armature 214 slidingly contacts with the brush 224, which generates brush-wear particles or motor-generated particles (referred to as ◯ in FIG. 31). Therefore, the fuel discharged from the second outlet port 230 of the fuel pump 201 contains motor-generated particles. The same problem happens in the fuel pumps disclosed in U.S. Pat. No. 6,739,354 and Japanese Laid-Open Publication No. 2002-303219.

This requires the high-pressure filter 330 to be provided at the back end of the fuel pump 201 so as to avoid the foreign particles generated in the motor section 202 (referred to as ◯ in FIG. 31) and the relatively small particles having passed through the low-pressure filter 332 (referred to as Δ in FIG. 31) from reaching the pressure regulator 286 or the injector 312 to cause troubles to the above-mentioned fuel supply system 284. At the same time, the low-pressure filter 332 needs to be provided at the front end of the fuel pump 201 so as to avoid the relatively large particles contained in the fuel within the reservoir cup 209 of the fuel tank 292 (referred to as ◯ in FIG. 31) from traveling into the fuel pump 201 to cause troubles.

Thus, the prior art fuel supply system 284 needs both the low-pressure filter 332 and the high-pressure filter 330. This forces the fuel supply system 284 to be in a large size. Especially when the low-pressure filter 332 is disposed at the lower end of the fuel pump as disclosed in U.S. Pat. No. 6,739,354, it is difficult to reduce the overall height of the fuel supply system 284. Another problem is the increased cost of the fuel supply system 284 because both the low-pressure filter 332 and the high-pressure filter 330 are required. This problem is also applicable to the fuel supply system of Japanese Laid-Open Publication No. 2002-303219.

In this respect, the pump of Netherlands Patent No. 6806734 solves such problems as having the motor-generated particles contained in the fluid discharged from the outlet port, because the fluid within the pump section can be discharged from the outlet port directly to the outside of the pump, without passing through the inside of the motor section. However, the fact that the fluid does not pass through the motor compartment results in another problem. The problem is that such a pump does not allow the fluid to cool the motor section, nor allow the fluid to lubricate the sliding portions, for example, between the armature shaft and the bearing, and between the armature commutator and the brush. Such a pump is undesirable for an in-tank fuel pump disposed, for example, in a fuel tank.

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to teach an electric pump and a fuel supply system with such electric pump that can discharge a fluid without motor-generated particles from the pump section directly to the outside of the pump, and can also cool the motor section and lubricate sliding portions with the fluid.

According to one embodiment of the present invention, an electric pump is taught that may include an outlet port (referred to as a “first outlet port” for the convenience of explanation) allowing a fluid drawn into the pump section and pressurized to be discharged directly to the outside of the pump. Thus, the fluid discharged from the pump compartment is discharged directly from the first outlet port, not through the motor compartment. This allows a fluid without motor-generated particles to be discharged from the pump section directly to the outside of the pump. It is to be noted that the description “to be discharged directly to the outside of the pump” refers to the fluid in the pump compartment being discharged from the pump compartment to the outside of the pump, not passing through the motor compartment or other flow paths. Also, the electric pump may further include a communicating opening allowing a portion of the fluid to flow from the pump section into the motor compartment. This enables the portion of the fluid to be guided from the pump section into the motor compartment through the communicating openings so as to cool the motor section and lubricate the sliding portions. It is to be noted that the description “sliding portions” refers to portions sliding between the stator elements (i.e. bearings, brush, and the like) and the rotor elements (i.e. a shaft and a commutator of the armature). The above-mentioned electric pump allows, on one hand, for discharging a fluid without motor-generated particles from the pump section directly to the outside of the pump, and on the other hand, for cooling the motor section and lubricating the sliding portions with the fluid.

According to another embodiment of the electric pump, the armature body is engaged with the impeller to transmit the torque thereto by an engagement means. This allows the axial length of the electric pump to be reduced, and therefore the electric pump to be miniaturized.

According to another embodiment of the electric pump, the communicating opening is provided at a point located after a quarter of the pumping cycle from the starting end to the terminating end in a single rotation of the impeller. This allows vapor or vapor bubbles generated in the fluid, for example, by elevated temperatures during the pumping cycle, to be effectively vented into the motor compartment via the communicating openings. It is to be noted that the vapor cannot be effectively vented at a point located before the quarter of the pumping cycle from the starting end in a single rotation of the impeller because the fluid has not built up enough pressure.

According to another embodiment of the electric pump, a vapor vent is provided to exit to the outside of the pump the vapor generated in the fluid during the pumping cycle in a single rotation of the impeller. This allows the vapor generated in the fluid, for example, by elevated temperatures during the pumping cycle, to be vented from the vapor vent to the outside of the pump. It is to be noted that the vapors can be effectively vented by providing the vapor vent at a point located after the quarter of the pumping cycle from the starting end in a single rotation of the impeller.

According to another embodiment of the electric pump, a second outlet port is provided in the pump to discharge to the outside of the pump the fluid discharged from the pump section into the motor compartment via the communicating opening. This allows the fluid discharged from the pump section into the motor compartment via the communicating opening to be discharged from the second outlet port to the outside of the pump. Therefore, the fluid passes within the motor compartment so that the cooling of the motor section and the lubricity of the sliding portions therewithin are increased.

According to another embodiment of the electric pump, the end cap member of the motor section is provided with the second outlet port. This allows the fluid discharged from the pump section into the motor compartment via the communicating openings to be discharged to the outside of the pump via the second outlet port, after passing from the pump side to the distal side of the motor compartment. Therefore, the fluid passes through substantially the overall length of the motor compartment so that the cooling of the motor section and the lubricity of the sliding portions within the motor section are further increased.

According to another embodiment of the electric pump, the second outlet port is provided with a check valve. This enables the check valve to prevent the fluid from flowing back from the outside of the pump into the motor compartment via the second outlet port.

According to another embodiment of the electric pump, the electric pump is provided with a jet pump driven by the fluid flow discharged from the second outlet port. This allows the fluid outside of the pump to be drawn and transferred to a predetermined position by using the fluid flow discharged from the second outlet port as a driving source. Therefore, it is possible to effectively use the pressure energy of the fluid flow discharged from the second outlet port.

According to another embodiment of the electric pump, the end cap member of the pump is provided with an outlet port (a first outlet port) discharging the fluid drawn into the pump section and then pressurized, directly to the outside of the pump. Thus, it is possible to discharge the fluid drawn into the pump section and then pressurized, from the first outlet port in the end cap member of the pump section directly to the outside of the pump.

According to another embodiment of the electric pump, the inlet port of the pump section opens through the outer side surface. This allows the fluid to be drawn into the pump section from the inlet port opening through the outer side surface.

According to one embodiment, a modularized fuel supply system is taught that may include an in-tank fuel pump drawing, pressurizing and discharging the fuel within the fuel tank, and a front-end filter removing foreign particles in the fuel drawn into the fuel pump. Furthermore, any one of the electric pumps of the above-mentioned embodiments is used as a fuel pump. Therefore, it is possible to provide a fuel supply system with an electric pump as a fuel pump that can discharge a fluid without motor-generated particles from the pump section directly to the outside of the pump, and can also cool the motor section and lubricate the sliding portions with the fluid. Also, it is possible to eliminate a high-pressure filter, which is required to be disposed at the back-end of the prior art fuel pump, because the fuel discharged from the outlet port (first outlet port) of the electric pump does not contain motor-generated particles. Thus, it is possible to make the fuel supply system compact and reduce the manufacturing cost. On the other hand, the front-end filter removes foreign particles, especially small particles, in a fuel drawn into the electric pump. Such small particles adversely affect the sliding portions of the electric pump. Therefore, it is possible to reduce or prevent troubles associated with the sliding portions so as to increase the electric motor life.

According to another embodiment of the modularized fuel supply system, the modularized fuel supply system includes an in-tank fuel pump drawing, pressurizing and discharging the fuel within the fuel tank, a front-end filter removing foreign particles in the fuel drawn into the fuel pump, and a reservoir cup disposed within the fuel tank to reserve a fuel drawn into the tank through the front-end filter by the fuel pump. Furthermore, any one of the electric pumps of the above-mentioned embodiments having a second outlet port is used as a fuel pump. Therefore, it is possible to provide a fuel supply system with an electric pump as a fuel pump that can discharge a fluid without motor-generated particles from the pump section directly to the outside of the pump, and can also cool the motor section and lubricate the sliding portions with the fluid. Also, it is possible to eliminate a high-pressure filter, which is required to be disposed at the back-end of the prior art fuel pump, because the fuel discharged from the outlet port (first outlet port) of the electric pump does not contain motor-generated particles. Thus, it is possible to make the fuel supply system compact and reduce the manufacturing cost. On the other hand, the front-end filter removes foreign particles in a fuel drawn into the electric pump, especially small particles adversely affecting the sliding portions of the electric pump. Therefore, it is possible to reduce or prevent troubles associated with the sliding portions to increase the electric motor life. Furthermore, the fuel supply system is provided with a jet pump driven by the fluid flow discharged from the second outlet port of the electric pump in order to transfer a fuel outside the reservoir cup but within the fuel tank into the reservoir cup. This enables the fuel outside of the reservoir cup but within the fuel tank to be drawn and then transferred into the reservoir cup by using the fluid flow (fuel flow) discharged from the second outlet port of the electric pump as a driving source to drive the jet pump. Therefore, it is possible to effectively use the pressure energy of the fuel flow discharged from the second outlet port of the electric pump.

According to another embodiment of the modularized fuel supply system, the modularized fuel supply system includes an in-tank fuel pump drawing, pressurizing and discharging the fuel within the fuel tank, a front-end filter removing foreign particles in the fuel drawn into the fuel pump, and a reservoir cup disposed within the fuel tank to reserve a fuel drawn into the cup through the front-end filter by the fuel pump. Furthermore, the electric pumps of the above-mentioned embodiments, having a jet pump driven by a fluid flow discharged from the second outlet port, is used as a fuel pump. Therefore, it is possible to provide a fuel supply system with an electric pump as a fuel pump that can discharge a fluid without motor-generated particles from the pump section directly to the outside of the pump, and can also cool the motor section and lubricate the sliding portions with the fluid. Also, it is possible to eliminate a high-pressure filter, which is required to be disposed at the back-end of the prior art fuel pump, because the fuel discharged from the outlet port (first outlet port) of the electric pump does not contain motor-generated particles. Thus, it is possible to make the fuel supply system compact and reduce the manufacturing cost. On the other hand, the front-end filter removes foreign particles in a fuel drawn into the electric pump, especially small particles adversely affecting sliding portions of the electric pump. Therefore, it is possible to reduce or prevent troubles associated with the sliding portions so as to increase the electric motor life. Furthermore, the fuel supply system is arranged and constructed to transfer a fuel from outside of the reservoir cup but within the fuel tank into the reservoir cup by the jet pump driven by the fluid flow discharged from the second outlet port of the electric pump. This enables the fuel outside of the reservoir cup but within the fuel tank to be drawn and then transferred into the reservoir cup by using the fluid flow (fuel flow) discharged from the second outlet port of the electric pump as a driving source to drive the jet pump. Therefore, it is possible to effectively use the pressure energy of the fuel flow discharged from the second outlet port of the electric pump.

According to another embodiment of the modularized fuel supply system, the front-end filter includes a filter element with a multilayer structure in which the outer layer is coarse while the inner layer is fine. This allows the front-end filter element to effectively remove foreign particles in a fuel drawn into the fuel pump.

According to another embodiment of the modularized fuel supply system, the front-end filter is provided with a filter element formed substantially cylindrical to surround the fuel pump. This wide area filtering allows the front-end filter element to effectively remove foreign particles in a fuel drawn into the fuel pump. This also allows the filtering area of the filter element to be increased so that the suction resistance is reduced. Therefore, it is possible to reduce the electric current consumption of the fuel pump.

According to another embodiment of the modularized fuel supply system, the modularized fuel supply system is provided with a pressure regulator. This allows the pressure regulator to control the fuel pressure of the pressurized fuel discharged from the fuel pump.

Furthermore, the pressure regulator may be disposed overlapping radially with respect to the fuel pump and the front-end filter. Therefore, it is possible to provide the fuel supply system compactly with the pressure regulator.

According to another embodiment of the fuel modularized supply system, the filter case is integrally formed with at least a portion of the regulator housing of the pressure regulator. Due to this, at least a portion of the regulator housing of the pressure regulator does not need to be provided separately. Therefore, it is possible to make the pressure regulator simplified and lightweight.

According to another embodiment of the modularized fuel supply system, the pressure regulator is fitted into the filter case with the mounting recesses provided on the filter case. This allows the pressure regulator, which is made as a discrete component, to be mounted easily to the mounting recesses provided on the filter case.

According to another embodiment of the modularized fuel supply system, the front-end filter is provided with an outlet path. The outlet path is connected with the outlet port (first outlet port) discharging the fuel, which is drawn into the pump section of the fuel pump, directly to the outside of the pump. The fuel discharged from the outlet port flows into a predetermined part through the outlet path. Thus, a dedicated component forming the outlet path is not required. This makes it possible to make the fuel supply system compact and lightweight, and reduce the manufacturing cost.

According to another embodiment of the modularized fuel supply system, the inlet port of the fuel pump is connected with the inlet path exit of the front-end filter in a fitting structure with a male port and a corresponding female port. This allows the connecting operation between the inlet port of the fuel pump and the inlet path exit of the front-end filter to be easily performed.

According to another embodiment of the modularized fuel supply system, a sealing member is interposed between the inlet port of the fuel pump and the inlet path exit of the front-end filter. This reduces or prevents fuel leakages from a connecting portion between the inlet port of the fuel pump and the inlet path exit of the front-end filter.

According to another embodiment of the modularized fuel supply system, the outlet path entrance of the front-end filter is connected with the outlet port of the fuel pump, which is connected with the outlet path entrance, in a fitting structure with a male port and a corresponding female port. This allows the connecting operation between the outlet path entrance of the front-end filter and the outlet port (first outlet port) of the fuel pump to be easily performed.

According to another embodiment of the modularized fuel supply system, a sealing member is interposed between the outlet path entrance of the front-end filter and the outlet port of the fuel pump. This reduces or prevents fuel leakages from a connecting portion between the outlet path entrance of the front-end filter and the outlet port (first outlet port) of the fuel pump.

According to another embodiment of the electric pump, the communicating opening is provided with a check valve. This enables the check valve to prevent the fluid, when the pump stops, from flowing back into the pump section through the communicating opening from the motor compartment. Therefore, it is possible to reduce or prevent a fluid containing motor-generated particles flowing from the first outlet port to the outside of the pump when the pump is operated again after the stop.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the claims and the accompanying drawings, in which:

FIG. 1 is a side elevational view, partly in cross section for clarity, of a fuel pump according to a first representative embodiment of the present invention;

FIG. 2 is a top view of the fuel pump according to the first representative embodiment;

FIG. 3 is a bottom view of the fuel pump according to the first representative embodiment;

FIG. 4 is a perspective view, showing the relationship between an inlet port and an outlet port of the fuel pump according to the first representative embodiment;

FIG. 5 is a cross sectional view of the pump section of the fuel pump according to the first representative embodiment;

FIG. 6 is a bottom view of the pump housing, showing a relationship between a flow channel and a communicating opening within the pump housing according to the first representative embodiment;

FIG. 7 is a flow path diagram of the fuel pump according to the first representative embodiment;

FIG. 8 is a cross sectional view of the pump section of a fuel pump according to a second representative embodiment of the present invention;

FIG. 9 is a view similar to FIG. 1, showing a fuel pump according to a third representative embodiment of the present invention;

FIG. 10 is a perspective view, showing the relationship between an inlet port and an outlet port of the fuel pump of FIG. 9;

FIG. 11 is a perspective view, showing a relationship between an inlet port and an outlet port of an alternative fuel pump according to the third representative embodiment;

FIG. 12 is a view similar to FIG. 5, showing a pump section of a fuel pump according to a fourth representative embodiment of the present invention;

FIG. 13 is a view similar to FIG. 1, showing a fuel pump according to a fifth representative embodiment of the present invention;

FIG. 14 is a view similar to FIG. 1, showing a fuel pump according to a sixth representative embodiment of the present invention;

FIG. 15 is a side elevational view, partly in cross section for clarity, of a modularized fuel supply system according to a seventh representative embodiment of the present invention;

FIG. 16 is a top view, partly in horizontal cross section for clarity, of the fuel supply system of FIG. 15;

FIG. 17 is an enlarged cross sectional view of the fuel supply system of FIG. 15, showing connecting portions between the front-end filter case and the fuel pump;

FIG. 18 is a flow path diagram of the fuel supply system of FIG. 15;

FIG. 19 is a view similar to FIG. 17, showing another fitting structure between the front-end filter case and the fuel pump;

FIG. 20 is a view similar to FIG. 17, showing yet another fitting structure between the front-end filter case and the fuel pump;

FIG. 21 is a view similar to FIG. 15, showing a modularized fuel supply system according to a seventh embodiment of the present invention;

FIG. 22 is a flow path diagram of the fuel supply system of FIG. 21;

FIG. 23 is a view similar to FIG. 15, showing a modularized fuel supply system according to a eighth representative embodiment of the present invention;

FIG. 24 is a perspective view showing the mounting recess of the filter case of FIG. 23.

FIG. 25 is a view similar to FIG. 15, showing a modularized fuel supply system according to a ninth representative embodiment of the present invention;

FIG. 26 is a view similar to FIG. 16, showing a modularized fuel supply system according to a tenth representative embodiment of the present invention;

FIG. 27 is a view similar to FIG. 17, showing a pump section of a fuel pump according to an eleventh representative embodiment of the present invention;

FIG. 28 is a view similar to FIG. 27, showing a pump section of a fuel pump according to a twelfth representative embodiment of the present invention;

FIG. 29 is a view similar to FIG. 21, showing a modularized fuel supply system according to a thirteenth representative embodiment of the present invention;

FIG. 30 is a side elevational view, partly in cross section for clarity, of the prior art fuel pump; and

FIG. 31 is a flow path diagram of the prior art fuel supply system of FIG. 30.

DETAILED DESCRIPTION OF THE INVENTION

Each of the additional features and teachings disclosed above and below may be utilized separately or in conjunction with other features and teachings to provide an improved electric pump and a fuel supply system with such electric pump. Representative examples of the present invention, which examples utilize many of these additional features and teachings both separately and in conjunction with each other, will now be described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Moreover, various features of the representative examples and the dependent claims may be combined in ways that are not specifically enumerated in order to provide additional useful embodiments of the present teachings.

Referring now to the drawings, representative embodiments of the present invention will be described below.

First Representative Embodiment

Turning now to the drawings, a fuel pump according to a first representative embodiment (hereinafter referred to as a “first representative fuel pump”) is shown in FIGS. 1 to 7.

Referring to FIG. 1, a fuel pump 1 is integrally provided with a motor section 2 and a pump section 3. The pump section 3 is disposed at one end of the motor section 2 (the lower end in FIG. 1). The outer shell of the fuel pump 1 is a pump casing 5, which includes a generally tubular shell 6, a motor cover 7 sealing one end of the tubular shell (the upper end in FIG. 1), a pump cover 8 sealing the other end of the tubular shell (the lower end in FIG. 1), and a pump housing 9 overlayingly provided on the pump cover 8 to partition the inside area of the pump casing 5 into a motor compartment 10 and a pump compartment 11. It is to be noted that the motor cover 7 is also referred to herein as an “end cap member of the motor section.” Similarly, the pump cover 8 is also referred to herein as an “end cap member of the pump section.” In the first representative fuel pump 1, a pump compartment 11 is defined by the pump cover 8 and the pump housing 9. The pump housing 9 is overlayingly provided on the pump cover 8. The upper surface of the pump cover 8 and the lower surface of the pump housing 9 define a cylindrical recess.

The motor section 2 will now be described. The motor section 2 consists, for example, of a brush-type DC motor, including magnets 13 secured within the tubular shell 6, and an armature 14 rotating within the tubular shell 6. The armature 14 includes an armature body 15 having an iron core, a coil, a commutator 16 and the like, and a shaft 18 provided through the axis of the armature body 15 in an up and down direction. One end (the upper end in FIG. 1) of the shaft 18 is rotatably supported within the motor cover 7 by a bearing 21. Meanwhile, the other end (the lower end in FIG. 1) of the shaft 18 passes through the pump housing 9, rotatably supported within the pump housing 9 by a bearing 22. The lower end of the shaft 18, which projects into the pump compartment 11, is a connecting portion 19 having a certain modified cross section such as a D-shaped cross section.

The motor cover 7 incorporates a brush 24 slidingly contacting with the commutator 16 of the armature 14, a spring 25 pushing the brush 24 onto the commutator 16, and the like. Furthermore, the motor cover 7 includes a connector section 28 having a terminal 27 electrically connected with the brush 24. Thus, the armature 14 is rotated by energizing the coil (not shown) of the armature 14 via the terminal 27, the brush 24, and the commutator 16.

The motor cover 7 is provided with an outlet port (referred to as a “second outlet port” for the convenience of explanation) 30 upwardly opening to the outside of the fuel pump 1. The second outlet port also communicates with the motor compartment 10. The motor cover 7 is also provided with a second outlet tube 31, which projects axially above the motor cover 7 and forms an outlet portion of the second outlet port 30.

Next, the pump section 3 will be described. As shown in FIG. 5, the pump compartment 11 is rotatably provided with a generally disk-shaped impeller 34. The outer periphery of the impeller 34 is provided with a plurality of vane grooves 35 at a circumferential predetermined interval. The vane grooves 35 on the top surface of the impeller 34 are in mirror symmetry with the vane grooves 35 of the bottom surface of the impeller 34. The vane grooves 35 on both surfaces communicates with each other through communicating holes 36. The center of the impeller 34 is provided with a shaft hole 38. The shaft hole 38 has a certain modified cross section such as a D-shaped cross section corresponding to the connecting portion 19 of the shaft 18 of the armature 14. The connecting portion 19 of the armature 14 is engagingly inserted into the shaft hole 38 so as to transmit the torque to the impeller 34.

As indicated with reference numerals 9 a and 8 a, the wall surfaces of the pump housing 9 and the pump cover 8, which respectively face the top and the bottom surfaces of the impeller 34, are provided with generally cylindrical recesses 39 corresponding respectively to the top and the bottom surfaces around the shaft hole 38 of the impeller 34. The recess 39 facing the top surface of the impeller 34 is substantially symmetrical to the recess 39 facing the bottom surface of the impeller 34. The recesses 39 of the pump cover 8 and the recess 39 of the pump housing 9 respectively define bearing compartments 63. Also, the wall surfaces 9 a and 8 a of the pump housing 9 and the pump cover 8 are provided with generally arc-shaped (such as C-shaped) flow channels 40 corresponding respectively to the vane grooves 35 on the top and the bottom surfaces of the impeller 34 (see FIG. 6).

The pump cover 8 is provided with an inlet port 42 downwardly opening to the outside of the fuel pump 1. The inlet port 42 communicates with the starting end of the flow channel 40. At the same time, the bottom surface of the pump cover 8 is provided with an inlet tube 43, which forms the entrance portion of the inlet port 42. Furthermore, the pump cover 8 is provided with an outlet port (referred to as a “first outlet port” for the convenience of explanation) 45 downwardly opening to the outside of the fuel pump 1. The first outlet port 45 also communicates with the terminating end of the flow channel 40. The bottom surface of the pump cover 8 is provided with a first outlet tube 45, which forms an exit portion of the first outlet port 45.

The pump housing 9 is provided with a communicating opening 48, opening to the motor compartment 10. The communicating opening 48 also communicates with a predetermined point between the starting end and the terminating end of the flow channel 40. It is to be noted that the first outlet port 45 and the communicating opening 48 in FIGS. 1 and 5 are in fact disposed apart at a predetermined angle along the circumferential direction of the impeller 34 (see FIG. 6). As shown in FIG. 6, the communicating opening 48 is provided at a point located after a quarter of the pumping cycle as defined from the starting end to the terminating end, in a single rotation of the impeller 34. The quarter of the pumping cycle (the entire cycle is shown as an angular part A) is shown as an angular part B. The communicating opening 48 is located within an angular part C. Providing the communicating opening 48 at a point located after the quarter of the pumping cycle allows vapor or vapor bubbles generated in the fluid or fuel, for example, by elevated temperatures during the pumping cycle, to be effectively vented into the motor compartment 10 through the communicating opening 48. It is to be noted that the vapor cannot be effectively vented if the communicating opening 48 is provided at a point located before a quarter of the pumping cycle (within angular part B in FIG. 6) because the fluid has not reached a sufficient pressure.

Now the operation of the above-mentioned fuel pump 1 is described. With respect to the motor section 2 (see FIG. 1), the armature 14 is initially rotated by energizing the coil (not shown) of the armature 14. Then, cooperating with the shaft 18 of the armature 14, the impeller 34 is rotated in a predetermined direction that creates a pumping action. This causes the flow channel 40 to draw a fluid or a fuel from the inlet port 42 of the pump cover 8 (see FIG. 5) through the starting end of the flow channel 40. Kinetic energy is applied to the fuel from the vane grooves 35 on the top and the bottom surfaces of the impeller 34, which communicate with each other through the communicating holes 36. The fuel is transferred through the flow channels 40 on both of the pump cover 8 and the pump housing 9, traveling from the starting end to the terminating end. In the course of the transfer, the fuel is gradually pressurized. Then, the fuel transferred to the terminating end of both flow channels 40 is discharged from the first outlet port 45 to the outside of the fuel pump 1. At the same time, the vapor contained in the fuel transferred in the pumping cycle through the rotation of the impeller 34 is vented into the motor compartment 10 of the motor section 2 via the communicating opening 48 of the pump housing 9. The vapor is then vented from the second outlet port 30 of the motor cover 7 (see FIG. 1).

The above-mentioned fuel pump 1 is provided with a first outlet port 45, which allows a fluid, drawn into the pump section and pressurized, to be discharged directly to the outside of the pump 1. Thus, the fluid is discharged directly from the pump section 3 via the first outlet port 45 of the pump section 3, not via the motor section 2 (see FIG. 7). This allows a fluid without motor-generated particles to be discharged from the pump section 3 directly to the outside of the fuel pump 1. On the other hand, the fuel pump 1 further includes a communicating opening 48 allowing a portion of the fluid to flow from the pump section 3 into the motor compartment 10 (see FIG. 5). This enables a portion of the fluid to be guided from the pump section 3 into the motor compartment 10 via the communicating opening 48 in order to cool the motor section 2 and lubricate the sliding portions. As described above, the fuel pump 1 allows, on one hand, for discharging a fluid without motor-generated particles from the pump section 3 directly to the outside of the pump 1, and on the other hand, for cooling the motor section 2 and lubricating the sliding portions with the fluid.

As shown in FIG. 6, the communicating opening 48 of the pump housing 9 is provided at a point located after a quarter of the pumping cycle as defined from the starting end to the terminating end in a single rotation of the impeller 34. This allows vapor generated in the fluid, for example, by elevated temperatures during the pumping cycle, to be effectively vented into the motor compartment 10 through the communicating opening 48.

As shown in FIG. 1, the fuel pump 1 is provided with a second outlet port 30, which allows a fuel discharged from the pump section 3 into the motor compartment 10 via the communicating opening 48 to be discharged to the outside of the fuel pump 1. This allows the fuel discharged from the pump section 3 into the motor compartment 10 via the communicating opening 48 to be discharged to the outside of the pump via the second outlet port 30. Therefore, the fuel passes through the motor compartment 10 so that the cooling of the motor section 2 and the lubricity of the sliding portions therewithin are increased.

As shown in FIGS. 1 and 2, the second outlet port 30 is provided in the motor cover 7, which is an end cap member of the motor section 2. This allows the fluid discharged from the pump section 3 into the motor compartment 10 via the communicating opening 48 to be discharged to the outside of the fuel pump 1 via the second outlet port 30, after passing from the pump side to the distal side of the motor compartment 10. Therefore, the fuel passes through substantially the overall length of the motor compartment 10 so that the cooling of the motor section 2 and the lubricity of the sliding portions within the motor section 2 are further increased.

As shown in FIG. 1, the fuel pump 1 is provided with the second outlet port 30, which allows a fuel discharged from the pump section 3 into the motor compartment 10 via the communicating opening 48 to be discharged to the outside of the fuel pump 1. This increases the fuel pump performance at elevated temperatures because vapor from the pump section 3 is easily vented upwardly to the communicating opening 48, the motor compartment 10, or the second outlet port 30.

As shown in FIGS. 1, 3, and 4, the pump cover 8, which is an end cap member of the pump section 3, is provided with the first outlet port 45. The first outlet port 45 allows a fluid drawn into the pump section 3 and pressurized to be discharged directly to the outside of the pump 1.

Second Representative Embodiment

Referring to FIG. 8, a fuel pump according to a second representative embodiment (hereinafter referred to as a “second representative fuel pump”) will be described. Since the second representative fuel pump is a modification of the first representative fuel pump, the description will be made only for the features that are different from the first representative fuel pump. As shown in FIG. 8, the second representative fuel pump 1 is modified in the shaft structure of the pump side of the armature 14 and the connection structure between the armature 14 and the impeller 34. As clearly understood when comparing with FIG. 5 of the first representative fuel pump 1, the pump side or the lower end of the shaft 18 has a generally round-bar-shaped shaft portion 18 a, without a connecting portion 19 (see FIG. 5). The lower shaft portion 18 a of the shaft 18 is rotatably supported by a bearing 50, which is mounted in the supporting hole 49 formed on the bottom surface of the pump cover recess 39.

On the other hand, the lower surface of the armature body 15 is axially provided with a generally cylindrical protrusion portion 52. The outer periphery of the lower surface of the protrusion portion 52 is provided with a predetermined number of engaging raised portions 53, the number of which is two in FIG. 8. Also, the protrusion portion 52 having the engaging raised portions 53 is loosely inserted into a through hole 55, which is formed in the pump housing 9. It is to be noted that the through hole 55 penetrates through the pump housing 9, the structure of which is different from the pump housing 9 of the first representative fuel pump 1 shown in FIG. 5. The recess 39 of the pump housing 9 shown in FIG. 5 is penetrated by a through hole 55 in the second representative fuel pump 1 shown in FIG. 8.

Meanwhile, the impeller 34 is provided with another through hole 57, which has a larger diameter than the outer diameter of the bearing 50. It is to be noted that the impeller 34 of the first representative fuel pump 1 shown in FIG. 5 is provided with the shaft hole 38 rather than the through hole 57 of the second representative fuel pump 1 shown in FIG. 8. The through hole 57 loosely receives the upper portion of the bearing 50. As shown in FIG. 8, the periphery of the top surface of the through hole 57 is provided with two engaging recessed portions 58, which respectively engage with the two raised engaging portions 53 of the armature 14. The engagement between the raised portions 53 and the recessed portions 58 allows the armature body 15 to transmit the torque to the impeller 34 at radially outer positions with respect to the shaft 18 (more specifically the lower shaft portion 18 a) of the armature 14. It is to be noted that the engaging raised portions 53 and the engaging recessed portions 58 are also referred to herein as “engagement means.”

It is also to be noted that the communicating opening 48 of the pump housing 9 of the first representative fuel pump 1 shown in FIG. 5 does not exist in the second representative fuel pump 1 shown in FIG. 8. Instead, the pump housing wall surface 9 a facing the impeller 34 is provided with communicating groove 60, which extends radially and allows the flow channel 40 to communicate with the through hole 55. The communicating groove 60 communicates with the motor compartment 10 via the through hole 55. On the other hand, the pump cover wall surface 8 a facing the impeller 34 is also provided with a communicating groove 61, which extends radially and allows the flow channel 40 to communicate with the recess 39. The communicating groove 61 communicates with the motor compartment 10 via the recess 39, the through hole 57 of the impeller 34, and the through hole 55 of the pump housing 9. It is to be noted that the communicating groove 60 of the pump housing 9 and the communicating groove 61 of the pump cover 8 are provided at a point located after a quarter of the pumping cycle as defined from the starting end to the terminating end in a single rotation of the impeller 34, similar to the communicating opening 48 of the first representative fuel pump 1.

As shown in FIG. 8, the armature body 15 transmits the torque to the impeller 34 through engagement means performed by the engagement raised portions 53 and the engagement recessed portions 58. This allows the axial (up and down direction in FIG. 8) length of the fuel pump 1 to be reduced. Therefore, the fuel pump 1 can be miniaturized. It is to be noted that the geometry of the engaging raised portions and the engaging recessed portions may be modified as long as the engagement between the raised portions 53 and the recessed portions 58 is ensured. It may also be possible to invert the positional relationship between the raised portions 53 and the recessed portions 58. Thus, the engaging recessed portions 58 may be provided on the armature body 15, while the engaging raised portion 53 may be provided on the impeller 34.

Meanwhile, referring to the pump housing 9, the vapor contained in the fuel transferred in the pumping cycle through the rotation of the impeller 34 are vented from the communicating groove 60 via the through hole 55 into the motor compartment 10 of the motor section 2. Also, referring to the pump cover 8, the vapor is vented from the communicating groove 61 via the recess 39, the through hole 57 of the impeller 34, and the through hole 55 of the pump housing 9 into the motor compartment 10 of the motor section 2. Then, the vapor is finally vented from the second outlet port 30 of the motor cover 7, after passing through the motor compartment 10, similar to the first representative fuel pump 1 shown in FIG. 1. This allows vapor generated in the fluid, for example, by elevated temperatures during the pumping cycle, to be effectively vented. It is to be noted that the “communicating opening” herein is defined by the through hole 55 and the communicating groove 60 in the pump housing 9, the recess 39 and the communicating groove 61 in the pump cover 8, and the through hole 57 of the impeller 34. Similarly, the “bearing compartment” herein is defined by the through hole 55 of the pump housing 9 and the recess of the pump housing 9.

As described above, since the communicating opening defined by the through holes 55 and 57, the communicating grooves 60 and 61, and the recess 39 discharges a portion of the fuel from the pump section 3 into the motor compartment 10, the fuel pressure within the motor compartment 10 is substantially equal to the fuel pressure within the bearing compartment (designated as reference numeral 64) defined by the through hole 55 of the pump housing 9 and the recess 39 of the pump housing 9. This makes it possible to make the fuel pump 1 more compact and lightweight, and reduce the manufacturing cost as compared to the prior art fuel pump for the following reasons.

(1) In the prior art fuel pump 201 shown in FIG. 30, the highly pressurized fuel flows from the pump section 203 into the motor compartment 210. Due to this, the fuel pressure within the motor compartment 210 is increased. Thus, also increased is the differential fuel pressure between the motor compartment 210 and the bearing compartment 263 defined by the pump housing 209 and the recess 239 of the pump cover 208. Therefore, the wall thickness of the pump housing 209 is required to be increased so as to be strong enough to resist the differential fuel pressure. Furthermore, since the connecting portion 219 of the shaft 218 of the armature 214 is loosely inserted into the shaft hole 238 of the impeller 234, the fuel pressure within the bearing compartment 263 of the pump housing 209 is generally equal to the fuel pressure within the bearing compartment 263 of the pump cover 208. This also requires the wall thickness of the pump cover 208 to be increased. In this manner, the increased wall thickness of both the pump cover 208 and the pump housing 209 results in the increased weight and also in the increased axial length of the fuel pump 201.

(2) In the prior art fuel pump 201 shown in FIG. 30, the clearance between the shaft 218 of the armature 214 and the bearing 222 provided in the pump housing 209 is reduced in order to avoid the reduced pump efficiency caused by a pressure leak from the pump compartment 211 into the motor compartment 210. However, the shaft length of the armature 214 is required to be long enough to ensure sufficient sealing between the motor compartment 210 and the bearing compartment 263. The long shaft 218 of the armature 214 results in the increased weight and also in the increased axial length of the fuel pump 201.

(3) In the prior art fuel pump 201 shown in FIG. 30, the connecting portion 219 of the shaft 218 of the armature 214 is required to be cut into a certain modified cross section, such as a D-shaped cross section, for connecting the shaft 218 to the impeller 234. This results in increased manufacturing cost.

Different from the above-mentioned prior art fuel pump 201 shown in FIG. 30, the second representative fuel pump 1 allows the fuel pressure within the motor compartment 10 to be equal to the fuel pressure within the bearing compartment 63 of the pump section 3. Thus, it is not necessary for the pump cover 8 and the pump housing 9 to resist the differential fuel pressure between the motor compartment 10 and the bearing compartment 63. This allows the wall thickness of the pump cover 8 and the pump housing 9 to be reduced. Therefore, the fuel pump 1 can be made compact and lightweight. Accordingly, the manufacturing cost can be reduced. Also, it is not necessary to seal between the motor compartment 10 and the bearing compartment 63. This allows the length of the shaft 18 of the armature 14 to be reduced. Therefore, the fuel pump 1 can be made compact and lightweight. Accordingly, the manufacturing cost can be reduced. Furthermore, it is not necessary to cut the shaft 18 into a certain modified cross section such as a D-shaped cross section for connecting the shaft 18 of the armature 14 to the impeller 34. Accordingly, the manufacturing cost can be reduced.

Third Representative Embodiment

Referring to FIGS. 9 and 10, a fuel pump according to a third representative embodiment (hereinafter referred to as a “third representative pump”) will be described. The third representative fuel pump is a modification of the first representative fuel pump. As shown in FIG. 9, the third representative fuel pump 1 is modified in that the second outlet port 30, defined by the second outlet tube 31 of the motor cover 7 of the first representative fuel pump 1, is provided with a check valve or a ball member 67. The lower portion of the second outlet port 30 within the second outlet tube 31 is provided with a valve seat 68, which is closed or opened by the ball member 67. On the other hand, the upper portion of the second outlet port 30 within the second outlet tube 31 is provided with a ball stopper 69, for example, formed in a C-shaped ring. The ball stopper 69 prevents the ball member 67 from ejecting out of the second outlet tube 31. When a fuel flows from the motor compartment 10 to the second outlet port 30, the check valve 67 is opened at the valve seat 68 and permits the fuel to be discharged to the outside of the pump. On the contrary, when a fuel flows back into the motor compartment 10 through the second outlet port 30, the check valve 67 is closed at the valve seat 68 and prevents the backflow of the fuel.

As shown in FIG. 10, the outer side surface of the fuel pump 1 is provided with a pair of inlet ports (designated as reference numeral 65) vertically aligned. This eliminates the inlet port 42 and the inlet tube 43 of the first representative fuel pump 1 shown in FIG. 1. As shown in FIG. 9, both of the inlet ports 65 penetrate radially through the tubular shell 6 of the pump casing 5, the pump cover 8, and the pump housing 9. The inlet ports 65, each of which has an opening on the tubular shell 6, respectively communicate with the starting ends of the flow channels 40 of the pump cover 8 and the flow channel 40 of the pump housing 9.

As shown in FIG. 9, the third representative fuel pump 1 is provided with a check valve 67 on the second outlet port 30 of the motor cover 7. This allows the check valve 67 to prevent the backflow of the fuel into the motor compartment 10 through the second outlet port from the outside of the pump.

Also, the fuel can be drawn into the pump section 3 from the inlet ports 65 of the outer side surface of the third representative fuel pump 1.

Other than the above-mentioned construction of the third representative fuel pump 1, the arrangement of the inlet port 42 and the first outlet port 45 may be modified as follows. As shown in FIG. 11, the inlet port (indicated as reference numeral 70) and the first outlet port (indicated as reference numeral 73) may be provided on the outer side surface of the fuel pump 1. As also shown in FIG. 11, an inlet tube 71 forming the entrance portion of the inlet port 70 and an outlet tube 74 forming the exit portion of the first outlet port 73 are projected from the outer side surface of the tubular shell 6.

Fourth Representative Embodiment

Referring to FIG. 12, a fuel pump according to a fourth representative embodiment (hereinafter referred to as a “fourth representative fuel pump”) will be described. The fourth representative fuel pump is a modification of the first representative fuel pump. As shown in FIG. 12, the fourth representative fuel pump 1 is provided with another vapor vent 76, which opens downwardly to the outside of the pump 1 and communicates with a predetermined point between the starting end and the terminating end of the flow channel 40. The vapor vent 76 is provided to exit vapor generated in the fluid during the pumping cycle in a single rotation of the impeller 34 to the outside of the pump 1. Similar to the communicating opening 48 of the first representative fuel pump 1, the vapor vent 76 is provided at a point located after a quarter of the pumping cycle starting from the starting end 42 (see FIG. 6).

The vapor vent 76 allows vapor generated in a fuel, for example, by elevated temperatures during the pumping cycle to be effectively vented from the pump compartment 11 to the outside of the pump 1. It is to be noted that the vapor can be effectively vented by providing the vapor vent 76 at a point located after a quarter of the pumping cycle from the starting end in a single rotation of the impeller 34.

Fifth Representative Embodiment

Referring to FIG. 13, a fuel pump according to a fifth representative embodiment (hereinafter referred to as a “fifth representative fuel pump”) will be described. The fifth representative fuel pump is a modification of the first representative fuel pump. As shown in FIG. 13, the fifth representative fuel pump 1 is modified in that the second outlet port 30 of the motor cover 7 is closed. Instead, there are a predetermined number of second outlet ports 78, the number of which is two shown in FIG. 13, formed in the tubular shell 6. The second outlet ports 78 penetrate at the upper end of the motor compartment 10, opening radially outward with respect to the tubular shell 6.

Sixth Representative Embodiment

Referring to FIG. 14, a fuel pump according to a sixth representative embodiment (hereinafter referred to as a “sixth representative fuel pump”) will be described. The sixth representative fuel pump is a modification of the first representative fuel pump. As shown in FIG. 14, the sixth representative fuel pump 1 is a modification of the first representative fuel pump 1 shown in FIG. 1. The motor cover 7 of the sixth representative fuel pump 1 is provided with a jet pump 80 driven by the fluid flow discharged from the second outlet port. It is to be noted that the terminal 27 and the connector section 28 of the first representative fuel pump 1 (see FIG. 1) are not shown in FIG. 14 for the convenience of explanation.

The jet pump 80 is provided with an exhaust port 81 opening upwardly and a suction port 82 opening laterally. When a fuel is discharged from the second outlet port 30, a negative pressure is generated in the jet pump 80. The negative pressure draws a fuel from the suction port 82, and then both of the fuels from the second outlet port 30 and the suction port 82 are mixed in the jet pump 80. The mixed fuels are discharged from the exhaust port 81. Thus, the jet pump 80 creates a pumping action to transfer a fuel to a predetermined part by using a fuel flow discharged from the second outlet port 30 as a driving source. Therefore, it is possible to effectively use the pressure energy of the fuel flow discharged from the second outlet port 30. As the basic configuration of a jet pump 80 is well known, the details thereof will not be described herein.

Seventh Representative Embodiment

Referring to FIGS. 15 to 17, a fuel supply system according to a seventh representative embodiment (hereinafter referred to as a “seventh representative fuel supply system”) will be described. This embodiment is a returnless fuel supply system, in which the first representative fuel pump (electric pump) 1 is provided as an in-tank fuel pump and no excess fuel from the engine is returned to the fuel tank. As shown in FIG. 15, the seventh representative fuel supply system 84 includes the first representative fuel pump 1, a front-end filter 85, a pressure regulator (regulator valve) 86, a jet pump 87, and a set plate 88. The seventh representative fuel supply system 84 is modularized and disposed in a reservoir cup (or merely referred to as a cup) 90 mounted within a fuel tank 92. The top of the fuel tank 92 is provided with an opening 93 for inserting the fuel supply system 84 into the fuel tank 92. The fuel tank 92 substantially sealingly defines a fuel receiving space when the opening 93 has been closed by the set plate 88. On the other hand, the reservoir cup 90, which is referred to as a “subtank” or “reserve cup,” is disposed in proximity of the bottom plate 92 a within the fuel tank 92. The reservoir cup 90 reserves a fuel, which flows into the cup 90 from within the fuel tank 92 and is drawn into the fuel pump 1.

Now the front-end filter 85 is described. The front-end filter 85 is an “integrated filter,” which serves as both the low-pressure filter 332 and the high-pressure filter 330 of the prior art fuel pump shown in FIG. 31. The front-end filter 85 also includes a filter case 95 and a filter element 96. The filter case 95 is made, for example, of a resin. As shown in FIG. 16, the filter case 95 has a generally tubular body 97 with a C-shaped cross section, within the hollow portion of which is provided the fuel pump 1. Also, the filter case 95 has a top wall 99, a bottom wall 100 (see FIG. 15), and end walls 101 (see FIG. 16), which define a filter compartment 98 on the outer periphery of the body 97. Furthermore, as shown in FIG. 15, the filter case 95 is provided with an inlet path 102, an outlet path 103, and a guiding path 104.

As shown in FIG. 15, the inlet path 102 extends from a lower portion of the filter case body 97 in a radially inner direction (the right-hand direction in FIG. 15), connecting a lower portion of the filter compartment 98 with the inlet port 42 of the fuel pump 1. As shown in FIG. 17, the downstream end of the inlet path 102 is provided with a path exit 106, which opens upwardly and serves as a female port fitting and receives the inlet tube 43 of the fuel pump inlet port 42 as a male port.

On the other hand, the outlet path 103 includes a transverse tube portion 107 extending from a lower portion of the filter case body 97 in a radially inner direction (the left-hand direction in FIG. 15), and a longitudinal tube portion 108, which continues from the outer end of the transverse tube portion 107 to form a generally L-shaped tube and extends in an upward direction along one end wall 101 of the filter case 95 (see FIG. 16). Then, the transverse tube portion 107 includes a path entrance 109, which opens upwardly at the inner end thereof and serves as a female port fitting and receives the outlet tube 46 of the fuel pump first outlet port 45 as a male port (see FIG. 17).

As shown in FIG. 15, the upper end of the longitudinal tube 108 of the outlet path 103 is connected with one end of the flexible connecting tube 110. The other end of the connecting tube 110 is connected with an internal-external communicating tube 89 provided through the set plate 88. The internal-external communicating tube 89 is connected with a fuel supply line 111 leading to an injector 112 (see FIG. 18) outside the fuel tank 92.

As shown in FIGS. 15 and 16, the guiding path 104 is a branching line of the outlet path 103. Also, as shown in FIG. 15, the guiding path 104 is disposed generally parallel to the longitudinal tube 108 of the outlet path 103. The pressure regulator 86 is provided on the upper end of the guiding path 104. As shown in FIGS. 15 and 16, the pressure regulator 86 is disposed overlapping radially with respect to the fuel pump 1 and the front-end filter 85. The pressure regulator 86 includes a regulator housing 114 having an upper half member 114 a and a lower half member 115. The lower half member 115 is integrally formed on the upper end of the guiding path 104. Components within the regulator housing 114 are incorporated into the lower half member 115.

As shown in FIG. 16, the filter element 96 is formed into a generally C-shaped cross sectional tube, which surrounds the outer periphery of the filter compartment 98 within the filter case 95. The filter element 96 is used for removing foreign particles drawn from within the reservoir cup 90 into the fuel pump 1. The filter element 96 is sealingly disposed surrounding the outer side opening of the filter compartment 98 of the filter case 95. The filter element 96 has a multilayer structure in which two filters consisting of an inner filter and an outer filter are radially overlayed in parallel with a predetermined clearance. The outer filter is formed with a coarse filter material 116 such as a fabric filter sheet. On the other hand, the inner filter is formed with a fine filter material 117 such as a paper filter. According to the above-mentioned filter structure, as a fuel flows in a arrow direction shown in FIG. 16, the coarse filter material 116 initially removes relatively large particles contained in the fuel. Then, the fine filter material 117 removes the relatively small particles and the brush-wear particles or motor-generated particles.

Next the pressure regulator 86 is described. As shown in FIG. 15, the pressure regulator 86 receives an incoming flow of a pressurized fuel from the fuel pump first outlet port 45 through the guiding path 104 of the filter case 95. Then, the pressure regulator 86 controls the pressure of the pressurized fuel discharged from the fuel pump 1 and drains an excess, pressurized fuel into the fuel tank 92, or more specifically, into the reservoir cup 90.

The jet pump 87 is described next. As shown in FIGS. 15 and 16, the jet pump 87 is provided in a lower part of the side wall 91 of the reservoir cup 90. Also, the jet pump 87 is provided with a fuel introducing port 120 opening upwardly, a fuel suction port 122 opening outside of the reservoir cup 90, and an exhaust port 121 opening into the reservoir cup 90. One end of the communicating tube 119 is connected to the second outlet tube 31 of the fuel pump 1, while the other end of the communicating tube 119 is connected to the fuel introducing port 120 of the jet pump 87, which is disposed within the reservoir cup 90. This allows the fuel discharged from the second outlet port 30 to flow into the fuel introducing port 120 through the communicating tube 119. The fuel introduced from the fuel introducing port 120 creates a negative pressure within the jet pump 87 when discharged from the exhaust port 121 into the reservoir cup 90. The negative pressure draws fuel from outside of the reservoir cup 90 via the fuel suction port 122. Then, the jet pump 87 discharges the mixed fuels from the exhaust port 121 into the reservoir cup 90. Thus, the jet pump 87 creates a pumping action to transfer fuel outside of the reservoir cup 90 into the jet pump 87 by using a fuel flow discharged from the second outlet port 30 of the fuel pump 1 as a driving source. As the basic configuration of a jet pump 87 is well known, the details thereof will not be described herein.

Now the operation of the above-mentioned fuel supply system 84 is described. As shown in FIG. 15, when the fuel pump 1 is activated, fuel within the reservoir cup 90 begins to flow. The fuel is filtered through the filter element 96 within the front-end filter 85 and flows into the filter compartment 98. Then, via the inlet path 102, the fuel is drawn into the pump section 3 from the inlet port 42 of the fuel pump 1. After pressurization in the pump section 3, the fuel is discharged from the first outlet port 45 to the outlet path 103 within the filter case 95. The pressurized fuel flows into the outlet path 103 and is eventually fed into the injector 112 (see FIG. 18) from the fuel supply line 111 outside of the set plate 88 via the connecting tube 110. It is to be noted that the injector 112 may be referred to as a target for the fuel to flow to.

As the pressure regulator 86 communicates with the outlet path 103 via the guiding path 104, the pressure of the pressurized fuel flowing into the outlet path 103 within the filter case 95 is controlled by the pressure regulator 86 so as to maintain a predetermined pressure. During the pressure control, excess, highly pressurized fuel is drained from the pressure regulator 86 into the reservoir cup 90. On the other hand, the fuel outside the reservoir cup 90 but within the fuel tank 92 is transferred into the reservoir cup 90 by the jet pump 87 using the fuel flow discharged from the second outlet port 30 of the fuel pump 1 as a driving source.

It is to be noted that when the fuel drawn into the fuel pump 1 passes through the filter element 96 of the front-end filter, the coarse filter material 116 firstly removes relatively large particles (referred to as □ in FIG. 18), and then the fine filter material 117 removes relatively small particles (referred to as Δ in FIG. 18). Furthermore, even if a fuel containing brush-wear particles or motor-generated particles (referred to as ◯ in FIG. 18) is discharged from the second outlet port 30 so as to flow into the jet pump 87 via the communicating tube 119 and then to pass through the coarse filter material 116 within the filter element 96 of the front-end filter 85. The motor-generated particles are ultimately removed with the fine filter material 117. This reduces or prevents motor-generated particles (referred to as ◯ in FIG. 18) from being drawn into the fuel pump 1.

The seventh representative fuel supply system 84 can discharge a fluid without motor-generated particles from the first outlet port 45, and can also cool the motor section 2 and lubricate sliding portions with the fluid.

Also, it is possible to eliminate a high-pressure filter 330 (see FIG. 31), which is required to be disposed at the back-end of the prior art fuel pump, because the fuel discharged from the fuel pump first outlet port 45 does not contain motor-generated particles. Thus, it is possible to make the fuel supply system 84 compact and reduce the manufacturing cost. It is to be noted that the prior art fuel supply system (see FIG. 31) requires both a low-pressure filter 332 and a high-pressure filter 330 so that the fuel supply system 284 is forced to be a large size. It is especially difficult to reduce the overall height of the fuel supply system 284 because the low-pressure filter 332 is disposed at the lower end of the fuel pump 201. In contrast, according to the seventh representative fuel supply system 84, it is possible to eliminate both the high-pressure filter 330 and the low-pressure filter 332 so that the fuel supply system 84 can be made compact. This results in reducing the manufacturing cost.

On the other hand, the front-end filter 85 removes foreign particles, especially small particles (referred to as Δ in FIG. 18) and motor-generated particles (referred to as ◯ in FIG. 18), in the fuel drawn into the fuel pump 1. Such small particles adversely affect the sliding portions of the fuel pump 1. Therefore, it is possible to reduce or prevent trouble with the sliding portions so as to increase the electric motor life. It is to be noted that the prior art fuel pump 201 allows the small particles, having already passed through the low-pressure filter 332, to pass further through the pump section 203 and the motor section 202 so that the life of the sliding portions in the fuel pump 201 may be largely reduced. In contrast, according to the seventh representative fuel supply system 84, the front-end filter 85 removes foreign particles, especially small particles (referred to as Δ in FIG. 18) and motor-generated particles (referred to as ◯ in FIG. 18) in the fuel drawn into the fuel pump 1. Such small particles would otherwise adversely affect the sliding portions of the fuel pump 1. Therefore, it is possible to reduce or prevent trouble with the sliding portions so as to increase the fuel pump life.

As described above, the fuel supply system 1 is provided with the jet pump 87 driven by the fluid flow discharged from the second outlet port 30 of the fuel pump 1 in order to transfer the fuel outside of the reservoir cup 90 but within the fuel tank 92 into the reservoir cup 90 (see FIGS. 15 and 16). Therefore, it is possible to effectively use the pressure energy of the fuel flow discharged from the second outlet port 30 of the fuel pump 1.

Also, the front-end filter 85 includes the filter element 96 with a multilayer structure in which the outer layer is coarse while the inner layer is fine (see FIGS. 15 and 16). This allows the front-end filter element 96 to effectively remove foreign particles in the fuel drawn into the fuel pump 1.

Furthermore, the front-end filter 85 has the filter element 96 formed substantially cylindrically so as to surround the fuel pump 1. This allows the filtering area of the filter element 96 to be increased so that the suction resistance is reduced. Therefore, it is possible to reduce the electric current consumption of the fuel pump 1.

Meanwhile, the fuel supply system 1 has a pressure regulator 86 controlling the fuel pressure of the fuel discharged from the fuel pump 1 (see FIGS. 15 and 16). Also, the pressure regulator 86 is disposed overlapping radially with respect to the fuel pump and the front-end filter (see FIGS. 15 and 16). Therefore, it is possible to compactly provide the fuel supply system 84 with the pressure regulator 86.

The filter case 95 is integrally formed with the lower half member 115 of the regulator housing 114 of the pressure regulator 86 (see FIG. 15). Due to this, the lower half member 115 or at least a portion of the regulator housing 114 of the pressure regulator 86 does not need to be provided separately. Therefore, it is possible to make the pressure regulator 86 simplified and lightweight.

As shown in FIGS. 15 and 16, the front-end filter 85 is provided with the outlet path 103 directly connected with the first outlet port 45 of the fuel pump 1. Thus, a dedicated component forming the outlet path 103 is not required. This makes it possible to make the fuel supply system 84 compact and lightweight, and reduce the manufacturing cost.

As shown in FIG. 17, the inlet tube 43 of the fuel pump 1 is connected with the inlet path exit 106 of the front-end filter 85, in a fitting structure with a male port and a corresponding female port. This allows the connecting operation between the inlet port 42 of the fuel pump 1 and the inlet path 102 of the front-end filter 85 to be easily performed.

On the other hand, as also shown in FIG. 17, the fuel pump outlet tube 46 is connected with the outlet path entrance 109 of the front-end filter 85 in a fitting structure with a male port and a corresponding female port. This allows the connecting operation between the fuel pump first outlet port 45 and the outlet path 103 of the front-end filter 85 to be performed easily.

More specifically, the fuel pump inlet port 42 is used as a corresponding male port, while the inlet path 102 of the front-end filter 85 is used as a female port, in such a manner that the front-end filter inlet path exit 106 fittingly receives the fuel pump inlet tube 43. Similarly, the outlet path 103 of the front-end filter 85 is used as a female port, while the fuel pump first outlet port 45 is used as a corresponding male port, in such a manner that the front-end filter inlet path entrance 109 fittingly receives the fuel pump outlet tube 46.

It is to be noted that the fitting structure shown in FIG. 17 may be modified within the scope of the present invention. As one alternative embodiment shown in FIG. 19, the inlet path exit 106 includes an exit tube 123 as a male port, while the fuel pump inlet port 42 is used as a corresponding female port, in such a manner that the fuel pump inlet tube 43 fittingly receives the front-end filter inlet exit 123.

Similarly, as also shown in FIG. 19, the outlet path entrance 103 is provided with an entrance tube 125 as a male port, while the fuel pump outlet tube 46 is used as a corresponding female port, in such a manner that the outlet tube 46 of the fuel pump first outlet port 45 fittingly receives the front-end filter outlet path entrance tube 125.

As another alternative embodiment shown in FIG. 20, sealing members 126 are interposed between the fuel pump 1 and the front-end filter 85. More specifically, on one hand, the rubber sealing member 126 is formed in a ring shape and is sandwiched between the pump cover 8 around the inlet port 42 and the top surface around the inlet path exit 106 of the front-end filter case 95. Similarly, such a sealing member 126 is also sandwiched between the pump cover 8 around the outlet tube 46 and the top surface around the outlet path entrance 109 of the front-end filter case 95. This reduces or prevents fuel leakages from connecting portions between the inlet port 42 of the fuel pump 1 and the inlet path exit 106 of the front-end filter case 95, and also between the outlet tube 46 of the fuel pump 1 and the outlet path entrance 109 of the front-end filter case 95. Furthermore, due to the resiliency of the sealing members 126, it is possible to reduce or prevent the vibration of the fuel pump 1 from transferring to the front-end filter case 95.

As yet another alternative embodiment shown in FIGS. 21 and 22, the jet pump 87 shown in 15, 16, and 18 may be eliminated. In this case, not only the jet pump 87, but also the communicating tube 119 may be eliminated.

Eighth Representative Embodiment

Referring to FIGS. 23 and 24, a fuel supply system according to an eighth representative embodiment (hereinafter referred to as an “eighth representative fuel supply system”) will be described. The eighth representative fuel supply system is a modification of the seventh representative fuel supply system. As shown in FIG. 23, the eighth representative fuel supply system is modified in that the lower half member 115 of the front-end filter case 95 according to the seventh representative embodiment (see FIG. 15) is replaced by a mounting recess 128. As shown in FIG. 24, the mounting recess 128 is formed at the upper end of the guiding path 104 of the filter case 95. The pressure regulator (designated as reference numeral 86A) fits downwardly into the mounting recess 128. It is to be noted that the pressure regulator 86A may be made as a discrete component apart from the filter case 95. This allows the pressure regulator to be easily fitted into the filter case 95 and enhances the modularity of the fuel supply system 84.

Ninth Representative Embodiment

Referring to FIG. 25, a fuel supply system according to a ninth representative embodiment (hereinafter referred to as a “ninth representative fuel supply system”) will be described. The ninth representative fuel supply system is a modification of the seventh representative fuel supply system. As shown in FIG. 25, the ninth representative fuel supply system is modified in that the fuel pump 1 of the seventh representative fuel supply system 84 (see FIG. 15) is replaced by the sixth representative fuel pump 1 with the jet pump 80 (see FIG. 14). This eliminates the jet pump 87 and the communicating tube 119 of the seventh representative fuel supply system shown in FIG. 15. Instead, the ninth representative fuel supply system is provided with a returning tube 130 and a introducing tube 132, which are connected with the jet pump 80 provided on the fuel pump 1. As shown in FIG. 25, the jet pump 80 of the fuel pump 1 according to the ninth representative embodiment is provided with the exhaust port 81, which is connected to one end of the returning tube 130. The other end of the returning tube 130 opens toward the bottom of the reservoir cup 90. On the other hand, the suction port 82 of the jet pump 80 is connected to one end of the introducing tube 132. The other end of the introducing tube 132 opens toward the bottom of the fuel tank 92, outside of the reservoir cup 90.

As shown in FIG. 25, the fuel outside the reservoir cup 90 but within the fuel tank 92 is drawn into the jet pump 80 via the introducing tube 132 by the jet pump 80 using the fuel flow discharged from the fuel pump second outlet port 30 (also see FIG. 14) as a driving source. Then, the fuel is discharged from the exhaust port 81 and transferred into the reservoir cup 90 via the returning tube 130. Therefore, it is possible to effectively use the pressure energy of the fuel flow discharged from the second outlet port 30 of the fuel pump 1.

Tenth Representative Embodiment

Referring to FIG. 26, a fuel supply system according to a tenth representative embodiment (hereinafter referred to as a “tenth representative fuel supply system”) will be described. The tenth representative fuel supply system is a modification of the seventh representative fuel supply system. It is to be noted that the pressure regulator 86, the jet pump 87, the outlet path 103, and the guiding path 104 (see FIG. 15) are not shown in FIG. 26 for the convenience of explanation. The filter case 95 of the tenth representative fuel supply system 84 is provided with an annular cross-sectional filter compartment 98A. The annular filter compartment 98A has a multilayer filter element 96A consisting of an outer filter or a coarse filter material 116A and an inner filter or a fine filter material 117A. The filter element 96A surrounds the fuel pump 1 located within the front-end filter element 96A, generally along the entire periphery of the fuel pump 1. This allows the front-end filter element 96A to effectively remove foreign particles in a fuel drawn into the fuel pump 1 in the direction shown by the arrows. Also, since the filtering area of the filter element 96A is increased more than the seventh representative fuel supply system, the fuel suction resistance of the fuel pump 1 may be more reduced. Therefore, it is possible to further reduce the electric current consumption of the fuel pump 1.

Eleventh Representative Embodiment

Referring to FIG. 27, a fuel supply system according to an eleventh representative embodiment (hereinafter referred to as an “eleventh representative fuel supply system”) will be described. The eleventh representative fuel supply system is a modification of the seventh representative fuel supply system. As shown in FIG. 27, the fuel pump 1 of the eleventh representative fuel supply system is modified in that the communicating opening 48 of the pump housing 9 according to the seventh representative embodiment (see FIG. 20) is provided with a check valve or a ball member 157. The lower and central portion of the communicating opening 48 is provided with a valve seat 158 that is closed or opened by the ball member 157. On the other hand, the upper portion of the communicating opening 48 is provided with a ball stopper 159, for example, formed as a C-shaped ring. The ball stopper 159 prevents the ball member 157 from ejecting out of the communicating opening 48. When fuel flows from the pump compartment 11 to the communicating opening 48, the check valve 157 is opened at the valve seat 158 and permits the fuel to be discharged into the motor compartment 10. On the contrary, when a fuel flows back into the pump compartment 11 through the communicating opening 48, the check valve 157 is closed at the valve seat 158 and prevents the backflow of the fuel.

This enables the check valve 157 to prevent the fuel from flowing back into the pump compartment 11 through the communicating opening 48 from the motor compartment 10 when the pump 1 stops. Therefore, even though the pump 1 stops, it is possible to block the fuel containing motor-generated particles within the motor compartment 10 from flowing into the pump compartment 11. Furthermore, it is possible to reduce or prevent the fuel containing motor-generated particles from being discharged into the outlet path 103 or to the outside of the pump 1 when the pump 1 is operated again after having been stopped.

Twelfth Representative Embodiment

Referring to FIG. 28, a fuel supply system according to a twelfth representative embodiment (hereinafter referred to as a “twelfth representative fuel supply system”) will be described. The eleventh representative fuel supply system is a modification of the seventh representative fuel supply system. As shown in FIG. 28, the fuel pump 1 of the twelfth representative fuel supply system is modified in that the upper portion of the inlet path exit 106 in the front-end filter case 95 is provided with an annular recess 106 a. In the annular recess 106 a is fitted a sealing member (designated as reference numeral 126) such as a resilient O-ring, which radially seals the fuel pump inlet tube 43 to the filter case inlet path exit 106. On the other hand, the upper portion of the outlet path entrance 109 in the front-end filter case 95 is provided with an annular recess 109 a. In the annular recess 109 a is fitted a sealing member (designated as reference numeral 126) such as a resilient O-ring, which radially seals the fuel pump outlet tube 46 to the filter case outlet path entrance 109. This reduces or prevents fuel leakages from connecting portions between the inlet port 42 of the fuel pump 1 and the inlet path exit 106 of the front-end filter case 95, and also between the outlet port 45 of the fuel pump 1 and the outlet path entrance 109 of the front-end filter case 95.

Furthermore, due to the resiliency of the sealing members 126, it is possible to reduce or prevent the vibration of the fuel pump 1 from transferring to the front-end filter case 95.

Thirteenth Representative Embodiment

Referring to FIG. 29, a fuel supply system according to a thirteenth representative embodiment (hereinafter referred to as a “thirteenth representative fuel supply system”) will be described. The thirteenth representative fuel supply system is a modification of the seventh representative fuel supply system. As shown in FIG. 29, the thirteenth representative fuel supply system is modified in that the front-end filter 85 of the seventh representative fuel supply system 84 (see FIG. 15) is replaced by a so-called suction filter. The suction filter is similar to the low-pressure filter 332 according to the prior art fuel supply system 284 shown in FIG. 31, and is herein referred to as a front-end filter 135. It is to be noted that the thirteenth representative fuel supply system 84 is displaced within the fuel tank 92 as shown in FIG. 29. Also, the reservoir cup 90 and the jet pump 87 of the seventh representative fuel supply system 84 shown in FIG. 15 are eliminated. In this case, the fuel tank 92 may be referred to as a reservoir.

The front-end filter 135 includes a filter material 136, which has a multilayer structure similar to the filter element 96 of the seventh representative fuel supply system. The filter material 136 removes relatively large particles, relatively small particles, and brush-wear particles contained in a fuel. The front-end filter 135 is provided with a mounting port 137 including a path entrance 146. The path entrance 146 serves as a female port which can fittingly receive a fuel pump inlet tube 43 as a corresponding male port.

The bottom surface of the set plate 88 is connected with a connecting tube 140 forming an outlet path 143 leading to an internal-external communicating tube 89. The connecting tube 140 includes a longitudinal tube portion 148 extending downwardly from the set plate 88 and a transverse tube portion 147 continuing transversely from the lower end of the longitudinal tube portion 148 to form a generally L-shaped tube. The transverse tube portion 147 includes a path entrance 149, which opens upwardly at the end in proximity to the fuel pump 1. The path entrance 149 serves as a female port, which fittingly receives the fuel pump outlet tube 46 as a corresponding male port. It is to be noted that the connecting tube 140 is integrally provided with a mounting port 137 of the front-end filter 135. Furthermore, the longitudinal tube portion 148 of the connecting tube 140 is provided with a pressure regulator 86 at the lower end wall of the longitudinal tube portion 148. The pressure regulator 86 controls the pressure of the pressurized fuel discharged from the fuel pump 1 and drains excess, pressurized fuel into the fuel tank 92. It is to be noted that the fuel pump 1 is provided with a cover member 150 surrounding the periphery of the fuel pump 1.

The operation of the above-mentioned fuel supply system 84 is as follows. When the fuel pump 1 is activated, the fuel within the fuel tank 92 begins to flow. The fuel is filtered through a filter element 136 within the front-end filter 135, and then is drawn into the pump section 3. After pressurization in the pump section 3, the fuel is discharged to the outlet path 143 of the connecting tube 140. The pressurized fuel discharged to the outlet path 143 is fed from the internal-external communicating tube 89 of the set plate 88 into the injector via a fuel supply line 111. On the other hand, since the pressure regulator 86 also communicates with the outlet path 143, the pressure of the pressurized fuel flowing into the outlet path 143 of the connecting tube 140 is controlled by the pressure regulator 86 so as to be a predetermined pressure. During the pressure control, excess, highly pressurized fuel is drained from the pressure regulator 86 into the fuel tank 92.

The invention has been described in detail with particular reference to certain representative embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. For example, the fuel pump according to the present invention may be generally applicable to other pumps in addition to a fuel pump. Also, the present invention may be applicable to multistage pumps including a plurality of impellers 34. Further, the present invention is applicable not only to a returnless fuel supply system 84, but also to a fuel supply system returning excess fuels from the engine side to the fuel tank 92. It is to be noted that at least one of the inlet port 42, the first outlet port 45, the second outlet port 30, communicating opening 48, and the vapor vent 76 of the fuel pump 1 may include a plurality of ports or openings. 

1. An electric pump comprising: a pump section including an impeller, an inlet port, and an outlet port, the pump section drawing a fluid into the pump section from the inlet port, pressurizing the fluid by a rotation of the impeller, and discharging the fluid directly to the outside of the electric pump via the outlet port; and a motor section including a rotatable armature and a motor compartment, the armature being disposed in the motor compartment and drives the impeller of the pump section, wherein the pump section is integrally assembled with the motor section and further includes a communicating opening allowing a portion of the fluid to flow from the pump section into the motor compartment.
 2. The electric pump as in claim 1, wherein the armature includes an armature body and a shaft projecting from the both ends of the armature body; and wherein the armature body is engaged with the impeller in such a manner that the armature body transmits the torque of the armature to the impeller at radially outer positions with respect to the shaft.
 3. The electric pump as in claim 1, wherein the communicating opening is provided at a point located after a quarter of a pumping cycle as defined from the starting end to the terminating end in a single rotation of the impeller.
 4. The electric pump as in claim 1 further comprising: a vapor vent exiting vapor generated in the fluid during a pumping cycle in a single rotation of the impeller to the outside of the pump.
 5. The electric pump as in claim 1 further comprising: a second outlet port discharging to the outside of the pump the fluid discharged from the pump section into the motor compartment via the communicating opening.
 6. The electric pump as in claim 5, wherein the motor section includes an end cap member that is provided with the second outlet port.
 7. The electric pump as in claim 5 further comprising: a check valve in the second outlet port.
 8. The electric pump as in claim 5 further comprising: a jet pump using a fluid flow discharged from the second outlet port as a driving source.
 9. The electric pump as in claim 1, wherein the pump section includes an end cap member that is provided with the outlet port discharging the drawn and pressurized fluid directly to the outside of the pump.
 10. The electric pump as in claim 1 further comprising: an outer side surface through which the inlet port of the pump section opens.
 11. The electric pump as in claim 1 further comprising: a check valve in the communicating opening.
 12. A modularized fuel supply system comprising: a fuel tank; an in-tank fuel pump drawing, pressurizing, and discharging a fuel within the fuel tank, the fuel pump being composed of an electric pump comprising; and a front-end filter removing foreign particles from the fuel drawn into the fuel pump, wherin the electric pump comprises: a pump section including an impeller, an inlet port, and an outlet port, the pump section drawing a fluid into the pump section from the inlet port, pressurizing the fluid by a rotation of the impeller, and discharging the fluid directly to the outside of the electric pump via the outlet port; and a motor section including a rotatable armature and a motor compartment, the armature being disposed in the motor compartment and drives the impeller of the pump section, wherein the pump section is integrally assembled with the motor section and further includes a communicating opening allowing a portion of the fluid to flow from the pump section into the motor compartment.
 13. A modularized fuel supply system comprising: a fuel tank; an in-tank fuel pump drawing, pressurizing, and discharging a fuel within the fuel tank, the fuel pump being composed of an electric pump; a front-end filter removing foreign particles from the fuel drawn into the fuel pump; and a reservoir cup disposed within the fuel tank to reserve a fuel drawn via the front-end filter by the fuel pump, wherein the electric pump comprises: a pump section including an impeller, an inlet port, and an outlet port, the pump section drawing a fluid into the pump section from the inlet port, pressurizing the fluid by a rotation of the impeller, and discharging the fluid directly to the outside of the electric pump via the outlet port; and a motor section including a rotatable armature and a motor compartment, the armature being disposed in the motor compartment and drives the impeller of the pump section, wherein the pump section is integrally assembled with the motor section and further includes a communicating opening allowing a portion of the fluid to flow from the pump section into the motor compartment, wherein the electric pump further includes a second outlet port discharging to the outside of the pump the fluid discharged from the pump section into the motor compartment via the communicating opening, and wherein the fuel supply system further includes a jet pump that uses a fluid flow discharged from the second outlet port of the electric pump as a driving source, and transfers a fuel from outside of the reservoir cup but within the fuel tank into the reservoir cup.
 14. A modularized fuel supply system for supplying a fuel to a comprising: a fuel tank; an in-tank fuel pump drawing, pressurizing, and discharging a fuel within the fuel tank, the fuel pump being composed of an electric pump; a front-end filter removing foreign particles from the fuel drawn into the fuel pump; and a reservoir cup disposed within the fuel tank to reserve a fuel drawn via the front-end filter by the fuel pump, wherein the electric pump comprises: a pump section including an impeller, an inlet port, and an outlet port, the pump section drawing a fluid into the pump section from the inlet port, pressurizing the fluid by a rotation of the impeller, and discharging the fluid directly to the outside of the electric pump via the outlet port; and a motor section including a rotatable armature and a motor compartment, the armature being disposed in the motor compartment and drives the impeller of the pump section, wherein the pump section is integrally assembled with the motor section and further includes a communicating opening allowing a portion of the fluid to flow from the pump section into the motor compartment, wherein the electric pump further includes a second outlet port discharging to the outside of the pump the fluid discharged from the pump section into the motor compartment via the communicating opening, and a jet pump using a fluid flow discharged from the second outlet port as a driving source, and wherein the jet pump of the electric pump uses a fluid flow discharged from the second outlet port of the electric pump as a driving source, and transfers a fuel from outside of the reservoir cup but within the fuel tank into the reservoir cup.
 15. The modularized fuel supply system as in claim 12, wherein the front-end filter includes a filter case in which a filter element is disposed; and wherein the filter element includes a multilayer structure in which the outer layer is coarse while the inner layer is fine.
 16. The modularized fuel supply system as in claim 12, wherein the front-end filter includes a filter case in which a filter element is disposed; and wherein the filter element is formed substantially cylindrically so as to surround the fuel pump.
 17. The modularized fuel supply system as in claim 12 further comprising: a pressure regulator controlling the fuel pressure of the pressurized fuel discharged from the fuel pump.
 18. The fuel supply system as in claim 16 further comprising: a pressure regulator controlling the fuel pressure of the pressurized fuel discharged from the fuel pump; wherein the pressure regulator is disposed overlapping radially with respect to the fuel pump and the front-end filter.
 19. The modularized fuel supply system as in claim 17, wherein the front-end filter includes a filter case in which a filter element is disposed; and wherein the pressure regulator includes a regulator housing, at least a portion of which is integrally formed with the filter case.
 20. The modularized fuel supply system as in claim 17, wherein the front-end filter includes a filter case in which a filter element is disposed; and wherein the filter case includes a mounting recesses, into which the pressure regulator is fitted.
 21. The modularized fuel supply system as in claim 12, wherein the front-end filter is provided with an outlet path including an outlet path entrance, which is connected with the outlet port of the fuel pump discharging a fuel drawn into the pump section of the fuel pump, directly to the outside of the pump; and wherein the fuel discharged from the outlet port flows into a predetermined part through the outlet path.
 22. The modularized fuel supply system as in claim 12, wherein the front-end filter is provided with an inlet path including an inlet path exit, which is connected with the inlet port of the fuel pump in a fitting structure with a male port and a corresponding female port.
 23. The modularized fuel supply system as in claim 22 further comprising: a sealing member interposed between the inlet port of the fuel pump and the inlet path exit of the front-end filter.
 24. The modularized fuel supply system as in claim 21, wherein the outlet path entrance of the front-end filter is connected with the outlet port of the fuel pump in a fitting structure with a male port and a corresponding female port.
 25. The modularized fuel supply system as in claim 24 further comprising: a sealing member interposed between the outlet path entrance of the front-end filter and the outlet port of the fuel pump.
 26. An electric pump for sending a fluid to a target, comprising: a pump section including an impeller, an inlet port, and first and second outlet ports, so that a fluid is drawn into the pump section via the inlet port and is discharged from the first and second outlet ports as the impeller rotates; and a motor section arranged and constructed to drive the impeller of the pump section, the motor section being integrally assembled with the pump section, wherein the fluid discharged from the first outlet port flows to the target, wherein the fluid discharged from the second outlet port flows through the motor section so as to cool the motor section and is then discharged to the outside of the pump.
 27. The electric pump as in claim 26 further comprising a casing for accommodating the pump section and the motor section within the casing, wherein the casing has a third outlet port, and wherein the motor section defines a flow path having a first end communicating with the second outlet and a second end communicating with the third outlet.
 28. The electric pump as in claim 27, wherein the motor section comprises an armature rotatably disposed within the casing and a pair of magnets attached to an inner wall of the casing, and wherein the flow path is defined between the armature and the magnets.
 29. A fluid supply system for supplying a fluid to a target, comprising the electric pump as in claim 26, and further comprising: a reservoir arranged and constructed to store the fluid, so that the fluid stored within the reservoir is drawn into the inlet port of the pump section of the electric pump, wherein the reservoir receives the supply of the fluid discharged from the electric pump via the second outlet port and the motor section; and a flow passage connected between the first outlet port and the target, so that the fluid is supplied to the target from the first outlet port. 